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path: root/drivers/watchdog/watchdog_dev.c
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Diffstat (limited to 'drivers/watchdog/watchdog_dev.c')
-rw-r--r--drivers/watchdog/watchdog_dev.c375
1 files changed, 289 insertions, 86 deletions
diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c
index 8558da912c4..672d169bf1d 100644
--- a/drivers/watchdog/watchdog_dev.c
+++ b/drivers/watchdog/watchdog_dev.c
@@ -42,10 +42,12 @@
#include <linux/init.h> /* For __init/__exit/... */
#include <linux/uaccess.h> /* For copy_to_user/put_user/... */
-/* make sure we only register one /dev/watchdog device */
-static unsigned long watchdog_dev_busy;
+#include "watchdog_core.h"
+
+/* the dev_t structure to store the dynamically allocated watchdog devices */
+static dev_t watchdog_devt;
/* the watchdog device behind /dev/watchdog */
-static struct watchdog_device *wdd;
+static struct watchdog_device *old_wdd;
/*
* watchdog_ping: ping the watchdog.
@@ -59,13 +61,26 @@ static struct watchdog_device *wdd;
static int watchdog_ping(struct watchdog_device *wddev)
{
- if (test_bit(WDOG_ACTIVE, &wddev->status)) {
- if (wddev->ops->ping)
- return wddev->ops->ping(wddev); /* ping the watchdog */
- else
- return wddev->ops->start(wddev); /* restart watchdog */
+ int err = 0;
+
+ mutex_lock(&wddev->lock);
+
+ if (test_bit(WDOG_UNREGISTERED, &wddev->status)) {
+ err = -ENODEV;
+ goto out_ping;
}
- return 0;
+
+ if (!watchdog_active(wddev))
+ goto out_ping;
+
+ if (wddev->ops->ping)
+ err = wddev->ops->ping(wddev); /* ping the watchdog */
+ else
+ err = wddev->ops->start(wddev); /* restart watchdog */
+
+out_ping:
+ mutex_unlock(&wddev->lock);
+ return err;
}
/*
@@ -79,16 +94,25 @@ static int watchdog_ping(struct watchdog_device *wddev)
static int watchdog_start(struct watchdog_device *wddev)
{
- int err;
+ int err = 0;
- if (!test_bit(WDOG_ACTIVE, &wddev->status)) {
- err = wddev->ops->start(wddev);
- if (err < 0)
- return err;
+ mutex_lock(&wddev->lock);
- set_bit(WDOG_ACTIVE, &wddev->status);
+ if (test_bit(WDOG_UNREGISTERED, &wddev->status)) {
+ err = -ENODEV;
+ goto out_start;
}
- return 0;
+
+ if (watchdog_active(wddev))
+ goto out_start;
+
+ err = wddev->ops->start(wddev);
+ if (err == 0)
+ set_bit(WDOG_ACTIVE, &wddev->status);
+
+out_start:
+ mutex_unlock(&wddev->lock);
+ return err;
}
/*
@@ -103,22 +127,155 @@ static int watchdog_start(struct watchdog_device *wddev)
static int watchdog_stop(struct watchdog_device *wddev)
{
- int err = -EBUSY;
+ int err = 0;
- if (test_bit(WDOG_NO_WAY_OUT, &wddev->status)) {
- pr_info("%s: nowayout prevents watchdog to be stopped!\n",
- wddev->info->identity);
- return err;
+ mutex_lock(&wddev->lock);
+
+ if (test_bit(WDOG_UNREGISTERED, &wddev->status)) {
+ err = -ENODEV;
+ goto out_stop;
}
- if (test_bit(WDOG_ACTIVE, &wddev->status)) {
- err = wddev->ops->stop(wddev);
- if (err < 0)
- return err;
+ if (!watchdog_active(wddev))
+ goto out_stop;
+ if (test_bit(WDOG_NO_WAY_OUT, &wddev->status)) {
+ dev_info(wddev->dev, "nowayout prevents watchdog being stopped!\n");
+ err = -EBUSY;
+ goto out_stop;
+ }
+
+ err = wddev->ops->stop(wddev);
+ if (err == 0)
clear_bit(WDOG_ACTIVE, &wddev->status);
+
+out_stop:
+ mutex_unlock(&wddev->lock);
+ return err;
+}
+
+/*
+ * watchdog_get_status: wrapper to get the watchdog status
+ * @wddev: the watchdog device to get the status from
+ * @status: the status of the watchdog device
+ *
+ * Get the watchdog's status flags.
+ */
+
+static int watchdog_get_status(struct watchdog_device *wddev,
+ unsigned int *status)
+{
+ int err = 0;
+
+ *status = 0;
+ if (!wddev->ops->status)
+ return -EOPNOTSUPP;
+
+ mutex_lock(&wddev->lock);
+
+ if (test_bit(WDOG_UNREGISTERED, &wddev->status)) {
+ err = -ENODEV;
+ goto out_status;
}
- return 0;
+
+ *status = wddev->ops->status(wddev);
+
+out_status:
+ mutex_unlock(&wddev->lock);
+ return err;
+}
+
+/*
+ * watchdog_set_timeout: set the watchdog timer timeout
+ * @wddev: the watchdog device to set the timeout for
+ * @timeout: timeout to set in seconds
+ */
+
+static int watchdog_set_timeout(struct watchdog_device *wddev,
+ unsigned int timeout)
+{
+ int err;
+
+ if ((wddev->ops->set_timeout == NULL) ||
+ !(wddev->info->options & WDIOF_SETTIMEOUT))
+ return -EOPNOTSUPP;
+
+ if ((wddev->max_timeout != 0) &&
+ (timeout < wddev->min_timeout || timeout > wddev->max_timeout))
+ return -EINVAL;
+
+ mutex_lock(&wddev->lock);
+
+ if (test_bit(WDOG_UNREGISTERED, &wddev->status)) {
+ err = -ENODEV;
+ goto out_timeout;
+ }
+
+ err = wddev->ops->set_timeout(wddev, timeout);
+
+out_timeout:
+ mutex_unlock(&wddev->lock);
+ return err;
+}
+
+/*
+ * watchdog_get_timeleft: wrapper to get the time left before a reboot
+ * @wddev: the watchdog device to get the remaining time from
+ * @timeleft: the time that's left
+ *
+ * Get the time before a watchdog will reboot (if not pinged).
+ */
+
+static int watchdog_get_timeleft(struct watchdog_device *wddev,
+ unsigned int *timeleft)
+{
+ int err = 0;
+
+ *timeleft = 0;
+ if (!wddev->ops->get_timeleft)
+ return -EOPNOTSUPP;
+
+ mutex_lock(&wddev->lock);
+
+ if (test_bit(WDOG_UNREGISTERED, &wddev->status)) {
+ err = -ENODEV;
+ goto out_timeleft;
+ }
+
+ *timeleft = wddev->ops->get_timeleft(wddev);
+
+out_timeleft:
+ mutex_unlock(&wddev->lock);
+ return err;
+}
+
+/*
+ * watchdog_ioctl_op: call the watchdog drivers ioctl op if defined
+ * @wddev: the watchdog device to do the ioctl on
+ * @cmd: watchdog command
+ * @arg: argument pointer
+ */
+
+static int watchdog_ioctl_op(struct watchdog_device *wddev, unsigned int cmd,
+ unsigned long arg)
+{
+ int err;
+
+ if (!wddev->ops->ioctl)
+ return -ENOIOCTLCMD;
+
+ mutex_lock(&wddev->lock);
+
+ if (test_bit(WDOG_UNREGISTERED, &wddev->status)) {
+ err = -ENODEV;
+ goto out_ioctl;
+ }
+
+ err = wddev->ops->ioctl(wddev, cmd, arg);
+
+out_ioctl:
+ mutex_unlock(&wddev->lock);
+ return err;
}
/*
@@ -136,6 +293,7 @@ static int watchdog_stop(struct watchdog_device *wddev)
static ssize_t watchdog_write(struct file *file, const char __user *data,
size_t len, loff_t *ppos)
{
+ struct watchdog_device *wdd = file->private_data;
size_t i;
char c;
@@ -175,23 +333,24 @@ static ssize_t watchdog_write(struct file *file, const char __user *data,
static long watchdog_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
+ struct watchdog_device *wdd = file->private_data;
void __user *argp = (void __user *)arg;
int __user *p = argp;
unsigned int val;
int err;
- if (wdd->ops->ioctl) {
- err = wdd->ops->ioctl(wdd, cmd, arg);
- if (err != -ENOIOCTLCMD)
- return err;
- }
+ err = watchdog_ioctl_op(wdd, cmd, arg);
+ if (err != -ENOIOCTLCMD)
+ return err;
switch (cmd) {
case WDIOC_GETSUPPORT:
return copy_to_user(argp, wdd->info,
sizeof(struct watchdog_info)) ? -EFAULT : 0;
case WDIOC_GETSTATUS:
- val = wdd->ops->status ? wdd->ops->status(wdd) : 0;
+ err = watchdog_get_status(wdd, &val);
+ if (err)
+ return err;
return put_user(val, p);
case WDIOC_GETBOOTSTATUS:
return put_user(wdd->bootstatus, p);
@@ -215,15 +374,9 @@ static long watchdog_ioctl(struct file *file, unsigned int cmd,
watchdog_ping(wdd);
return 0;
case WDIOC_SETTIMEOUT:
- if ((wdd->ops->set_timeout == NULL) ||
- !(wdd->info->options & WDIOF_SETTIMEOUT))
- return -EOPNOTSUPP;
if (get_user(val, p))
return -EFAULT;
- if ((wdd->max_timeout != 0) &&
- (val < wdd->min_timeout || val > wdd->max_timeout))
- return -EINVAL;
- err = wdd->ops->set_timeout(wdd, val);
+ err = watchdog_set_timeout(wdd, val);
if (err < 0)
return err;
/* If the watchdog is active then we send a keepalive ping
@@ -237,21 +390,21 @@ static long watchdog_ioctl(struct file *file, unsigned int cmd,
return -EOPNOTSUPP;
return put_user(wdd->timeout, p);
case WDIOC_GETTIMELEFT:
- if (!wdd->ops->get_timeleft)
- return -EOPNOTSUPP;
-
- return put_user(wdd->ops->get_timeleft(wdd), p);
+ err = watchdog_get_timeleft(wdd, &val);
+ if (err)
+ return err;
+ return put_user(val, p);
default:
return -ENOTTY;
}
}
/*
- * watchdog_open: open the /dev/watchdog device.
+ * watchdog_open: open the /dev/watchdog* devices.
* @inode: inode of device
* @file: file handle to device
*
- * When the /dev/watchdog device gets opened, we start the watchdog.
+ * When the /dev/watchdog* device gets opened, we start the watchdog.
* Watch out: the /dev/watchdog device is single open, so we make sure
* it can only be opened once.
*/
@@ -259,6 +412,13 @@ static long watchdog_ioctl(struct file *file, unsigned int cmd,
static int watchdog_open(struct inode *inode, struct file *file)
{
int err = -EBUSY;
+ struct watchdog_device *wdd;
+
+ /* Get the corresponding watchdog device */
+ if (imajor(inode) == MISC_MAJOR)
+ wdd = old_wdd;
+ else
+ wdd = container_of(inode->i_cdev, struct watchdog_device, cdev);
/* the watchdog is single open! */
if (test_and_set_bit(WDOG_DEV_OPEN, &wdd->status))
@@ -275,6 +435,11 @@ static int watchdog_open(struct inode *inode, struct file *file)
if (err < 0)
goto out_mod;
+ file->private_data = wdd;
+
+ if (wdd->ops->ref)
+ wdd->ops->ref(wdd);
+
/* dev/watchdog is a virtual (and thus non-seekable) filesystem */
return nonseekable_open(inode, file);
@@ -286,9 +451,9 @@ out:
}
/*
- * watchdog_release: release the /dev/watchdog device.
- * @inode: inode of device
- * @file: file handle to device
+ * watchdog_release: release the watchdog device.
+ * @inode: inode of device
+ * @file: file handle to device
*
* This is the code for when /dev/watchdog gets closed. We will only
* stop the watchdog when we have received the magic char (and nowayout
@@ -297,6 +462,7 @@ out:
static int watchdog_release(struct inode *inode, struct file *file)
{
+ struct watchdog_device *wdd = file->private_data;
int err = -EBUSY;
/*
@@ -310,7 +476,10 @@ static int watchdog_release(struct inode *inode, struct file *file)
/* If the watchdog was not stopped, send a keepalive ping */
if (err < 0) {
- pr_crit("%s: watchdog did not stop!\n", wdd->info->identity);
+ mutex_lock(&wdd->lock);
+ if (!test_bit(WDOG_UNREGISTERED, &wdd->status))
+ dev_crit(wdd->dev, "watchdog did not stop!\n");
+ mutex_unlock(&wdd->lock);
watchdog_ping(wdd);
}
@@ -320,6 +489,10 @@ static int watchdog_release(struct inode *inode, struct file *file)
/* make sure that /dev/watchdog can be re-opened */
clear_bit(WDOG_DEV_OPEN, &wdd->status);
+ /* Note wdd may be gone after this, do not use after this! */
+ if (wdd->ops->unref)
+ wdd->ops->unref(wdd);
+
return 0;
}
@@ -338,62 +511,92 @@ static struct miscdevice watchdog_miscdev = {
};
/*
- * watchdog_dev_register:
+ * watchdog_dev_register: register a watchdog device
* @watchdog: watchdog device
*
- * Register a watchdog device as /dev/watchdog. /dev/watchdog
- * is actually a miscdevice and thus we set it up like that.
+ * Register a watchdog device including handling the legacy
+ * /dev/watchdog node. /dev/watchdog is actually a miscdevice and
+ * thus we set it up like that.
*/
int watchdog_dev_register(struct watchdog_device *watchdog)
{
- int err;
-
- /* Only one device can register for /dev/watchdog */
- if (test_and_set_bit(0, &watchdog_dev_busy)) {
- pr_err("only one watchdog can use /dev/watchdog\n");
- return -EBUSY;
+ int err, devno;
+
+ if (watchdog->id == 0) {
+ watchdog_miscdev.parent = watchdog->parent;
+ err = misc_register(&watchdog_miscdev);
+ if (err != 0) {
+ pr_err("%s: cannot register miscdev on minor=%d (err=%d).\n",
+ watchdog->info->identity, WATCHDOG_MINOR, err);
+ if (err == -EBUSY)
+ pr_err("%s: a legacy watchdog module is probably present.\n",
+ watchdog->info->identity);
+ return err;
+ }
+ old_wdd = watchdog;
}
- wdd = watchdog;
-
- err = misc_register(&watchdog_miscdev);
- if (err != 0) {
- pr_err("%s: cannot register miscdev on minor=%d (err=%d)\n",
- watchdog->info->identity, WATCHDOG_MINOR, err);
- goto out;
+ /* Fill in the data structures */
+ devno = MKDEV(MAJOR(watchdog_devt), watchdog->id);
+ cdev_init(&watchdog->cdev, &watchdog_fops);
+ watchdog->cdev.owner = watchdog->ops->owner;
+
+ /* Add the device */
+ err = cdev_add(&watchdog->cdev, devno, 1);
+ if (err) {
+ pr_err("watchdog%d unable to add device %d:%d\n",
+ watchdog->id, MAJOR(watchdog_devt), watchdog->id);
+ if (watchdog->id == 0) {
+ misc_deregister(&watchdog_miscdev);
+ old_wdd = NULL;
+ }
}
-
- return 0;
-
-out:
- wdd = NULL;
- clear_bit(0, &watchdog_dev_busy);
return err;
}
/*
- * watchdog_dev_unregister:
+ * watchdog_dev_unregister: unregister a watchdog device
* @watchdog: watchdog device
*
- * Deregister the /dev/watchdog device.
+ * Unregister the watchdog and if needed the legacy /dev/watchdog device.
*/
int watchdog_dev_unregister(struct watchdog_device *watchdog)
{
- /* Check that a watchdog device was registered in the past */
- if (!test_bit(0, &watchdog_dev_busy) || !wdd)
- return -ENODEV;
-
- /* We can only unregister the watchdog device that was registered */
- if (watchdog != wdd) {
- pr_err("%s: watchdog was not registered as /dev/watchdog\n",
- watchdog->info->identity);
- return -ENODEV;
+ mutex_lock(&watchdog->lock);
+ set_bit(WDOG_UNREGISTERED, &watchdog->status);
+ mutex_unlock(&watchdog->lock);
+
+ cdev_del(&watchdog->cdev);
+ if (watchdog->id == 0) {
+ misc_deregister(&watchdog_miscdev);
+ old_wdd = NULL;
}
-
- misc_deregister(&watchdog_miscdev);
- wdd = NULL;
- clear_bit(0, &watchdog_dev_busy);
return 0;
}
+
+/*
+ * watchdog_dev_init: init dev part of watchdog core
+ *
+ * Allocate a range of chardev nodes to use for watchdog devices
+ */
+
+int __init watchdog_dev_init(void)
+{
+ int err = alloc_chrdev_region(&watchdog_devt, 0, MAX_DOGS, "watchdog");
+ if (err < 0)
+ pr_err("watchdog: unable to allocate char dev region\n");
+ return err;
+}
+
+/*
+ * watchdog_dev_exit: exit dev part of watchdog core
+ *
+ * Release the range of chardev nodes used for watchdog devices
+ */
+
+void __exit watchdog_dev_exit(void)
+{
+ unregister_chrdev_region(watchdog_devt, MAX_DOGS);
+}